面试题60：把二叉树打印成多行

/*
struct TreeNode {
int val;
struct TreeNode *left;
struct TreeNode *right;
TreeNode(int x) :
val(x), left(NULL), right(NULL) {
}
};
*/
class Solution {
public:
vector<vector<int> > Print(TreeNode* pRoot) {
vector<vector<int>> result;
if(!pRoot)
return result;
int toBePrinted = 1;
int nextLevel = 0;
queue<TreeNode*> q;
q.push(pRoot);
vector<int> v;
while(!q.empty()){
TreeNode* pCur = q.front();
q.pop();
v.push_back(pCur->val);
--toBePrinted;
if(pCur->left){
q.push(pCur->left);
++nextLevel;
}

if(pCur->right){
q.push(pCur->right);
++nextLevel;

}
if(!toBePrinted){
result.push_back(v);
v.clear();
toBePrinted = nextLevel;
nextLevel = 0;
}
}
return result;
}

};